When somebody opens a listing from your clip and buys it within 7 days, and the order is released, 20% of the seller fee on it is yours — out of Selivont's fee, so the seller pays nothing more. A clip of your own listing earns nothing extra. It is paid to your Stripe account 14 days after the order is released, once payouts are set up there. It waits for the same things a seller's release waits for, and while a chargeback on the sale is being decided.
If part of the sale goes back to the buyer before it is paid, the commission shrinks by the same share, and if all of it does, nothing is paid. After it is paid, a refund or a chargeback decided for the buyer means you owe back the same share; it comes out of your next commission or sale before anything else is paid to you. A commission on a clip a moderator takes down, or on an account that is closed or banned, is not paid.
Commissions are income, and tax on them is yours to work out. When a year's commissions reach $2,000, we file a Form 1099 for them with the details you gave Stripe, and you get a copy.